I'm Michelle Franzen in New York as the financial markets closed in New York on Thursday April 24. This is story stuck and today we're looking at FaceBook shares in the social media site jumped on an excellent earnings report but now. In a little bit flat here to talk about the -- love hate relationship with FaceBook Aaron task from Yahoo! finance. -- FaceBook had an excellent first quarter reporting some outstanding numbers. Give us an idea of what's at play there. Well that they've really the ball out of the park -- mean their earnings and their revenue of 2.5 billion dollars was up 72%. Much better -- she was looking for and they have figured out how to make money off. These devices offer mobile devices which a year ago every once it was going to be the big challenge and could they pull it off and -- -- -- -- -- really -- wet. How do they do it what do you think is behind this uptick. Right well. I think they have figured out a way you get advertisements. Onto apps -- and that's that's been a real trick and ended -- in a way that hasn't offended. -- users and that's been a big challenge because. When they started rolling out ads on FaceBook on the desktop a lot of these said well -- we don't want these ads and they had a scaled back. But they they have figured out a way to do it on the mobile devices and people are responding to them and advertisers more partly -- -- him -- mobile ad revenue. Was more than 50% of their total ad revenue and it was about one point three billion dollars. Up 59 a series of 9%. Of their ad revenue as -- said end again they just continue to blow way to street ex expectations for -- Not a bad job as we look at the two -- -- chart we see investors revved up. And cool down why. Some really good question I mean this stock came out of the -- this morning it was up about 5%. Treated well over 63 dollars. And then fell sharply from there are two under sixty dollars and then back up again to around almost 63 dollars and then back down. To end the day almost unchanged in and around 61. And I think the big question for investors is now. Valuation. The stock is not cheap -- price to earnings basis. And so even know that they are. Growing so dramatically a lot of it's already priced into the stock that's kind of that I don't -- -- -- negative but that's the case for why the stock hasn't gone. Didn't go much higher today I'm so they're doing everything they're supposed to do but the street was anticipating it I think maybe that's the best way to put -- You know with all these fast moving social sites what does FaceBook need to do to keep this train -- And our investors worried about the saturation point perhaps being eclipsed by Twitter snapped -- All those younger. You younger sites that they like to use. Right well FaceBook still has the secure weapon of instant Graham which they acquired a couple of years ago for a billion dollars in people said that Mark Zuckerberg was crazy to spend that much money needs to Graham. And being announced in their earnings that they now are -- at -- excuse and are at -- million users on -- to -- alone which is roughly the size of twitters audience. So it's a huge audience younger demographic. And presumably the next big push for FaceBook is -- it to monetize that to roll out advertisements on -- -- And Mark Zuckerberg Sheryl Sandberg on their conference -- -- they're gonna do it but they're going to very slowly because again they don't wanna -- their users and the teens are much more sensitive. To advertisement but that that's really the next big. Opportunity. For FaceBook and the potential challenge for them is okay we've got a lot more users. -- -- Graham and that's where we're growing how -- we make money from. That very important yet fickle demographic Aaron -- -- of Yahoo! finance thank you for joining us. Even watching stories stocks stay with abcnews.com. For your latest headlines I'm Michelle Franzen in New York.

This transcript has been automatically generated and may not be 100% accurate.